Microbiology• Updated 21 October 2026
COVID-19 Test (RT-PCR and Rapid Antigen)
Tests on a nose or throat swab that detect the virus that causes COVID-19.
Results: Rapid test: 15–30 minutes; RT-PCR: within a day Specimen: Nose or throat swab
Quick Summary
Primary Purpose
To diagnose COVID-19.
What It Measures
Viral genetic material (RT-PCR) or viral proteins (rapid antigen).
Preparation
Avoid eating or drinking for 30 minutes before a throat swab.
Overview
RT-PCR is more sensitive; rapid antigen tests are faster.
A negative rapid test may need confirming if symptoms continue.
What It Measures
RT-PCR
Viral RNA.
Rapid antigen
Viral proteins.
How It's Performed
- 01
Sample
A soft swab is gently rubbed on the area.
- 02
Lab
The swab is sent for testing.
- 03
Results
Your doctor contacts you with results.
Interpreting Results & Next Steps
Discuss with Doctor
Your doctor will explain what your result means and what happens next.
If values are High:
A positive result means infection; follow medical advice and isolation guidance.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- PCR Tests(opens in a new tab) · MedlinePlus, US National Library of Medicine
- COVID-19 testing(opens in a new tab) · NHS